Java tutorial
/******************************************************************************* * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html *******************************************************************************/ package org.summer.dsl.xbase.ui.contentassist; import java.util.ArrayList; import java.util.List; import org.eclipse.core.runtime.Assert; import org.eclipse.jdt.internal.ui.text.JavaHeuristicScanner; import org.eclipse.jface.preference.JFacePreferences; import org.eclipse.jface.resource.JFaceResources; import org.eclipse.jface.text.BadLocationException; import org.eclipse.jface.text.IDocument; import org.eclipse.jface.text.IRegion; import org.eclipse.jface.text.ITextViewer; import org.eclipse.jface.text.TextPresentation; import org.eclipse.jface.text.contentassist.IContextInformation; import org.eclipse.swt.SWT; import org.eclipse.swt.custom.StyleRange; import org.eclipse.swt.graphics.Image; import org.eclipse.xtext.ui.editor.contentassist.ISmartContextInformation; import com.google.common.collect.Lists; /** * This class is mainly adopted from {@link org.eclipse.jdt.internal.ui.text.java.ProposalContextInformation} * and friends. * @see org.eclipse.jdt.internal.ui.text.java.JavaParameterListValidator * @author Sebastian Zarnekow - Initial contribution and API * @noextend This class is not intended to be subclassed by clients. * @noinstantiate This class is not intended to be instantiated by clients. */ public class ParameterContextInformation implements ISmartContextInformation { private final ParameterData data; private final String contextDisplayString; private int parameterListOffset; private int currentParameter = -1; private int initialCarretOffset; public ParameterContextInformation(ParameterData data, String contextDisplayString, int parameterListOffset, int initialCarretOffset) { this.data = data; this.contextDisplayString = contextDisplayString; this.parameterListOffset = parameterListOffset; this.initialCarretOffset = initialCarretOffset; } @Override public boolean equals(Object object) { if (object instanceof IContextInformation) { IContextInformation contextInformation = (IContextInformation) object; boolean equals = getInformationDisplayString() .equalsIgnoreCase(contextInformation.getInformationDisplayString()); if (getContextDisplayString() != null) equals = equals && getContextDisplayString().equalsIgnoreCase(contextInformation.getContextDisplayString()); return equals; } return false; } @Override public int hashCode() { int low = getContextDisplayString() != null ? getContextDisplayString().hashCode() : 0; return (getInformationDisplayString().hashCode() << 16) | low; } public String getInformationDisplayString() { return data.getDisplayString(); } public List<String> internalGetInformationDisplayString() { return data.getRawDisplayString(); } public Image getImage() { // TODO implement return null; } public String getContextDisplayString() { return contextDisplayString; } public int getContextInformationPosition() { return initialCarretOffset; } public boolean isContextInformationValid(ITextViewer viewer, int position) { try { if (position < this.parameterListOffset) return false; IDocument document = viewer.getDocument(); IRegion line = document.getLineInformationOfOffset(this.parameterListOffset); if (position < line.getOffset() || position >= document.getLength()) return false; return getCharCount(document, this.parameterListOffset, position, "(<", ")>", false) >= 0; //$NON-NLS-1$ //$NON-NLS-2$ } catch (BadLocationException x) { return false; } } public boolean updatePresentation(ITextViewer viewer, int position, TextPresentation presentation) { int currentParameter = -1; try { currentParameter = getCharCount(viewer.getDocument(), this.parameterListOffset, position, ",", "", //$NON-NLS-1$//$NON-NLS-2$ true); } catch (BadLocationException x) { return false; } if (currentParameter != -1) { if (currentParameter == this.currentParameter) return false; } presentation.clear(); this.currentParameter = currentParameter; List<String> rawStrings = internalGetInformationDisplayString(); List<int[]> commaArrays = Lists.newArrayList(); for (String s : rawStrings) { commaArrays.add(computeCommaPositions(s)); } int offset = 0; for (int i = 0; i < rawStrings.size(); i++) { String raw = rawStrings.get(i); int[] commas = commaArrays.get(i); if (commas.length - 2 < this.currentParameter && !data.isVarArgs(i)) { presentation.addStyleRange(new StyleRange(offset, raw.length(), JFaceResources.getColorRegistry().get(JFacePreferences.QUALIFIER_COLOR), null, SWT.NORMAL)); } else { int actualParameter = this.currentParameter; if (actualParameter + 1 >= commas.length) actualParameter = commas.length - 2; int start = commas[actualParameter] + 1; int end = commas[actualParameter + 1]; if (start > 0) presentation.addStyleRange(new StyleRange(offset, start, null, null, SWT.NORMAL)); if (end > start) presentation.addStyleRange(new StyleRange(offset + start, end - start, null, null, SWT.BOLD)); if (end < raw.length()) presentation.addStyleRange( new StyleRange(offset + end, raw.length() - end, null, null, SWT.NORMAL)); } offset += raw.length() + 1; } return true; } protected int[] computeCommaPositions(String code) { final int length = code.length(); int pos = 0; List<Integer> positions = new ArrayList<Integer>(); positions.add(new Integer(-1)); while (pos < length && pos != -1) { char ch = code.charAt(pos); switch (ch) { case ',': positions.add(new Integer(pos)); break; case '<': pos = advance(code, length, pos, '<', '>'); break; case '[': pos = advance(code, length, pos, '[', ']'); break; case '(': pos = advance(code, length, pos, '(', ')'); break; default: break; } if (pos != -1) pos++; } positions.add(new Integer(length)); int[] fields = new int[positions.size()]; for (int i = 0; i < fields.length; i++) fields[i] = positions.get(i).intValue(); return fields; } protected int advance(String code, final int length, int pos, char left, char right) { int remaining = 1; pos++; while (pos < length && pos != -1 && remaining > 0) { char ch2 = code.charAt(pos); if (ch2 == left) remaining++; else if (ch2 == right) remaining--; pos++; } return pos; } // see JavaParameterListValidator protected int getCharCount(IDocument document, final int start, final int end, String increments, String decrements, boolean considerNesting) throws BadLocationException { Assert.isTrue((increments.length() != 0 || decrements.length() != 0) && !increments.equals(decrements)); final int NONE = 0; final int BRACKET = 1; final int BRACE = 2; final int PAREN = 3; final int ANGLE = 4; int nestingMode = NONE; int nestingLevel = 0; int charCount = 0; int offset = start; while (offset < end) { char curr = document.getChar(offset++); switch (curr) { case '/': if (offset < end) { char next = document.getChar(offset); if (next == '*') { // a comment starts, advance to the comment end offset = getCommentEnd(document, offset + 1, end); } else if (next == '/') { // '//'-comment: nothing to do anymore on this line int nextLine = document.getLineOfOffset(offset) + 1; if (nextLine == document.getNumberOfLines()) offset = end; else offset = document.getLineOffset(nextLine); } } break; case '*': if (offset < end) { char next = document.getChar(offset); if (next == '/') { // we have been in a comment: forget what we read before charCount = 0; ++offset; } } break; case '"': case '\'': offset = getStringEnd(document, offset, end, curr); break; case '[': if (considerNesting) { if (nestingMode == BRACKET || nestingMode == NONE) { nestingMode = BRACKET; nestingLevel++; } break; } //$FALL-THROUGH$ case ']': if (considerNesting) { if (nestingMode == BRACKET) if (--nestingLevel == 0) nestingMode = NONE; break; } //$FALL-THROUGH$ case '(': if (considerNesting) { if (nestingMode == ANGLE) { // generics heuristic failed nestingMode = PAREN; nestingLevel = 1; } if (nestingMode == PAREN || nestingMode == NONE) { nestingMode = PAREN; nestingLevel++; } break; } //$FALL-THROUGH$ case ')': if (considerNesting) { if (nestingMode == PAREN) if (--nestingLevel == 0) nestingMode = NONE; break; } //$FALL-THROUGH$ case '{': if (considerNesting) { if (nestingMode == ANGLE) { // generics heuristic failed nestingMode = BRACE; nestingLevel = 1; } if (nestingMode == BRACE || nestingMode == NONE) { nestingMode = BRACE; nestingLevel++; } break; } //$FALL-THROUGH$ case '}': if (considerNesting) { if (nestingMode == BRACE) if (--nestingLevel == 0) nestingMode = NONE; break; } //$FALL-THROUGH$ case '<': if (considerNesting) { if (nestingMode == ANGLE || nestingMode == NONE && checkGenericsHeuristic(document, offset - 1, start - 1)) { nestingMode = ANGLE; nestingLevel++; } break; } //$FALL-THROUGH$ case '>': if (considerNesting) { if (nestingMode == ANGLE) if (--nestingLevel == 0) nestingMode = NONE; break; } //$FALL-THROUGH$ default: if (nestingLevel != 0) continue; if (increments.indexOf(curr) >= 0) { ++charCount; } if (decrements.indexOf(curr) >= 0) { --charCount; } } } return charCount; } protected int getCommentEnd(IDocument d, int pos, int end) throws BadLocationException { while (pos < end) { char curr = d.getChar(pos); pos++; if (curr == '*') { if (pos < end && d.getChar(pos) == '/') { return pos + 1; } } } return end; } protected int getStringEnd(IDocument d, int pos, int end, char ch) throws BadLocationException { while (pos < end) { char curr = d.getChar(pos); pos++; if (curr == '\\') { // ignore escaped characters pos++; } else if (curr == ch) { return pos; } } return end; } protected boolean checkGenericsHeuristic(IDocument document, int end, int bound) { JavaHeuristicScanner scanner = new JavaHeuristicScanner(document); return scanner.looksLikeClassInstanceCreationBackward(end, bound); } }